The idiosyncrasies of human decision-making have confounded economists and social theorists for years. If each person makes choices for personal (and often irrational) reasons, how can people's choices be predicted? What if someone told you that the way to understand human behavior is through physics rather than psychology? Computer modeling now enables us to look at humans as 'social atoms', and here we find that our collective behavior follows precise mathematical patterns. If we study patterns, not people, then rules emerge that explain how movements form, how interest groups operate and even why ethnic hatred persists. Using similar observations we can predict whether neighborhoods will integrate, whether stock markets will crash and whether crime waves will continue or abate. This new 'social physics' will allow us to understand and predict a wide variety of human behavior-with consequences in everything from marketing and advertising to social reform and political movements.